Prof Peter Norreys FInstP;

Abstract:

Lateral and axial thermal energy transport in laser-plasma interactions has been studied using a short (12 psec) pre-pulse free KrF pumped Raman laser pulse (λ = 268 nm) of low beam divergence. A new method of producing narrow line foci using random phase plates was employed to study the plasma conditions required to generate high gain, short wavelength recombination X-ray lasers. In addition, the laser energy was focused into a small focal spot (8 μm) for higher intensity (1-2 × 1017 cm-2) interaction studies.

Abstract:

Recent progress in developing KrF laser pumped Raman lasers has shown their potential as X-ray laser drivers. The combination of short wavelength (268 nm) with low beam divergence and high beam intensity gives the possibility of very high focused intensity in very narrow line foci. An 8 cm × 8 cm beam combining Raman amplifier in the Sprite system has generated 0.4 TW, 12 ps pulses with 20 μrad beam divergence. A 10 μm wide line focus has been produced and plasmas from a NaF target have been studied at irradiances up to 3 × 1014 W cm-2. Numerical simulations suggest that the Sprite system should be able to produce high recombination gain in F IX at 8.1 nm and that larger scale KrF pumped Raman lasers which are being considered for future UK and European facilities would be ideal drivers for Mg XII at 4.5 nm.